Structs and typedef: . vs ->

English

Grouping related data

A struct groups several values into one thing. A point has an x and a y; a rectangle has a width and a height.
Each value inside is called a member (or field). They can have different types.
Structs let you pass one tidy thing around instead of many loose variables.

Bahasa Indonesia

Mengelompokkan data terkait

Sebuah struct mengelompokkan beberapa nilai menjadi satu kesatuan. Titik memiliki x dan y; persegi panjang memiliki width dan height.
Setiap nilai di dalamnya disebut anggota (atau field). Mereka bisa memiliki tipe berbeda.
Struct memungkinkan Anda mengirim satu kesatuan rapi alih-alih banyak variabel berserakan.

A Point struct with x and y; reach a field with . on the struct, or -> through a pointer

English

struct and typedef

You define the shape once: struct { int x; int y; } has two int members.
typedef gives that shape a short name. After typedef struct { int x; int y; } Point;, you can write Point p;.
In these tasks, the typedef is already written for you in the starter.

Bahasa Indonesia

struct dan typedef

Anda mendefinisikan bentuk sekali: struct { int x; int y; } memiliki dua anggota int.
typedef memberikan nama pendek bagi bentuk itu. Setelah typedef struct { int x; int y; } Point;, Anda dapat menulis Point p;.
Dalam tugas-tugas ini, typedef sudah ditulis untuk Anda di starter.

English

Member access with .

For a struct value, use a dot: p.x is the x member of p.
You read it (int a = p.x;) and write it (p.y = 5;) just like a normal variable.
A function can build a struct, fill its members, and return the whole thing.

Bahasa Indonesia

Akses anggota dengan .

Untuk nilai struct, gunakan titik: p.x adalah anggota x dari p.
Anda membacanya (int a = p.x;) dan menuliskannya (p.y = 5;) seperti variabel biasa.
Fungsi dapat membangun struct, mengisi anggotanya, dan return keseliannya.

English

Through a pointer with ->

When you have a pointer to a struct, use an arrow: p->x means "the x of what p points to".
p->x is just shorthand for (*p).x. The arrow is easier to read.
Passing a Point * lets a function change the caller's struct (like pass-by-pointer for one value).

Bahasa Indonesia

Melalui pointer dengan ->

Ketika Anda memiliki pointer ke struct, gunakan tanda panah: p->x berarti "x dari apa yang ditunjuk oleh p".
p->x hanyalah singkatan dari (*p).x. Tanda panah lebih mudah dibaca.
Meneruskan Point * memungkinkan fungsi mengubah struct pemanggil (seperti pass-by-pointer untuk satu nilai).

#include <stdio.h>

typedef struct {
    int x;
    int y;
} Point;

int main(void) {
    Point p = {3, 4};
    Point *ptr = &p;
    ptr->x = 10;                    // changes p.x through the pointer
    printf("%d %d\n", p.x, p.y);    // 10 4
    return 0;
}

English

Common mistakes

Use . on a struct value and -> on a struct pointer.
typedef lets you drop the word struct when declaring.

Bahasa Indonesia

Kesalahan umum

Gunakan . pada nilai struct dan -> pada pointer struct.
typedef memungkinkan Anda menghilangkan kata struct saat mendeklarasikan.

English

Now you try

Use . on a struct value, and -> when you have a pointer to a struct.
The typedef is given in each starter. Do not write a main — the checker provides one.

Bahasa Indonesia

Sekarang Anda coba

Gunakan . pada nilai struct, dan -> ketika Anda memiliki pointer ke struct.
typedef disediakan di setiap starter. Jangan tulis main — checker menyediakan sendiri.

Complete Point make_point(int x, int y) so it builds a Point with those values and returns it (use . on the members). The typedef is given. Do not write a main.

typedef struct {
    int x;
    int y;
} Point;

/* Build a Point with the given x and y, then return it. Do not write main(). */
Point make_point(int x, int y) {
    Point p;
    p.x = 0;   /* change this */
    p.y = 0;   /* change this */
    return p;
}

Click Run to see the output here. · ⁨Klik Jalankan untuk melihat output di sini.⁩

Complete void move_point(Point *p, int dx, int dy) so it adds dx to the point's x and dy to its y, using ->. The typedef is given. Do not write a main.

typedef struct {
    int x;
    int y;
} Point;

/* Move the point by (dx, dy) using ->. Do not write main(). */
void move_point(Point *p, int dx, int dy) {
    /* change p->x and p->y */
}

Click Run to see the output here. · ⁨Klik Jalankan untuk melihat output di sini.⁩

Complete int rect_area(const Rect *r) so it returns width * height, reading the members with ->. The typedef is given. Do not write a main.

typedef struct {
    int width;
    int height;
} Rect;

/* Return width * height using r->. Do not write main(). */
int rect_area(const Rect *r) {
    return 0;   /* use r->width and r->height */
}

Click Run to see the output here. · ⁨Klik Jalankan untuk melihat output di sini.⁩

Grouping related data

Mengelompokkan data terkait

struct and typedef

struct dan typedef

Member access with .

Akses anggota dengan .

Through a pointer with ->

Melalui pointer dengan ->

Common mistakes

Kesalahan umum

Now you try

Sekarang Anda coba

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